AORTIC COARCTATION: WHAT IS AORTIC COARCTATION?
Definition: What is "Aortic coarctation"?
Aortic coarctation is a condition characterized by narrowing of the aorta in an area where the "ductus arteriosus" inserts. There are three types of aortic coarctation - preductal, ductal & postductal coarctation. In preductal coarctation, the narrowing is near the ductus arteriosus. Severe cases of preductal coarctation, blood flow to the lower body to the narrowing could become dependent on a patent ductus arteriosus. When this happens, its closure can become life threatening & lead to hypoplastic development of the aorta. In ductal coarctation, the narrowing occurs along the insertion of the "ductus arteriosus". This type of condition usually develops when the ductus arteriosus closes. In postductal coarctation, the narrowing is far from the instertion of the ductus arteriosus. Newborns with this type of aortic coarctation may become critically sick after birth. Ductal aortic coarctation is more common in adults & is associated with hypertension, weak pulses in lower extremeties & notching of the ribs.
Symptoms & Signs
Patients with aortic coarctation develop arterial hypertension in their right arm with normal (or low) blood pressure in their lower extremities. Most patients with severe aortic coarctation have poor peripheral pulses in their "Femoral" arteries. If the aortic coarctation is located before the left "subclavian artery", patients will experience synchronous radial pulses in their left & right arms. There would be a radial-femoral delay between their right arms. However, the left arm would have no delay; instead, radial-femoral palpitations would occur. If the aortic coarctation is located after the left "subclavian artery", patients will experience synchronous radial pulses. In addition, radial-femoral delay will also be present in either arm.
Aortic coarctation can be diagnosed accurately through magnetic resonance angiography. However, if this condition occurs in adolescents & adults, echocardiograms may not be conclusive. Since aortic coarctation in adults usually reach the lower body, these could be seen by angiography or MR.
If aortic coarctation is asymptomatic, but shows arterial hypertension, it could still require surgical resection of the narrow segment. However, some cases may require angioplasty to dilate the narrowed arteries. Aortic coarctation left untreated may lead to permanent arterial hypertension because of irreversible changes in the patients' organs.